env: script to generate VM image for netbsd-amd64.

This uses anita to install and configure NetBSD.

Update golang/go#8643

Change-Id: Iba1e75a65314380339d0c88370ab7cc5d08e78de
Reviewed-on: https://go-review.googlesource.com/19350
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
4 files changed